Cadillac Repair/overflow


I have a 99 cadi deville. My issue is my coolant system is pushing antifreeze back to my reservoir nd it iscome out of the overflow. I have replaced cap nd thermostat wat else could be my problem other than maybe a blocked hose. Once is dispenses the fluid then will start to overheat.


Head gaskets? This aluminum engine cannot be overheated a little bit. With 50/50 anti freeze if you run the engine at 225 degrees, your engine is melting! Even the 225 degrees is pushing it. These engines are not available in a junk yard either, because they are all overheated junk!

You could have a hole in a cylinder wall and that would give you the same issue. Everyone thinks they can correct the overheating by changing the thermostat and up to this point, everyone has been wrong.
Radiator could be plugged, cooling system circulation problem, fans not working and more. These engines are great for performance and economy, but their Achilles heel is over heating.

Many people think they have a cast iron engine where they can run this engine hot until they get some place safe. If you do not shut it off immediately with the hot light on (usually too late) or when the engine is getting in the 220s, catastrophic damage is going on!

Also be aware, head gaskets are not the cause of overheating this engine, but the result and will set you back $1,500.00 plus. A GM crate engine is $4K plus change.
Look at my archives f people that have met the same peril as you.

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Rob Painter


Alarm system questions cannot be answered on this forum. These systems are not what I can answer. Without being physically at the vehicle and not knowing what kind of electrical service has been done on the vehicle, there is no possible way to give an accurate answer over the internet. My expertise is in Ignition/key based anti-theft systems. These issues include GM VATS (resistor chip in key blade) PASSLOCK (MRD)-ignition lock rotation based, no special ignition key and the PKIII Transponder (computer chip in key) systems. These systems are not alarm based and are integral with the starting of the engine. This is why I cannot diagnose alarm problems without physically looking at the vehicle: Alarm systems are a completely different annimal than ignition key/lock based anti-theft system. Many alarm questions come from vehicles 10 years old, and since older, many hands that had been involved over the years.I am an expert in all GM factory (ignition/key based)systems. Alarm system questions pose to many situations beyond my knowledge as to what has been done to the vehicle over the years. Some guy may have actually wired the stereo into the alarm system. Who knows? Over my past 30 years in vehicle wiring repair, I have seen unbelievable wiring disaters done by guys that consider themselves "mechanics." I have seen stereos and alarms intalled using surgical tape. I have seen modules burn up, un-fused circuits, wiring jambed between the doors and even lamp cord used for a starter kill. To answer alarm questions over the internet without examining the vehicle is like asking; What does it take to remove a dent?


Education/Credentials-ASE certified. 11 years with a GM dealer and 17 years with a repair facility dealing with only the repair of theft recovered vehicles.

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